Zone selector actuated by vent line



Feb. 11, 1969 C. MURRAY, JR

ZONE SELECTOR ACTUA'IED BY VENT LINE Sheet Filed 'Feb. 8, 1967 FIG. 2

INVENTOR. Y CLARENCE MURRAY JR.

BY MARCUS L. BATES Feb. 11, 1969 c MURRAY, JR -3,426,6 87

ZONE SELECTOR ACTUATED BY VENT LINE Filed Feb. 8, 1967 Sheet 2 of 2 I I l 60 I I I INVENTOR. H CLARENCE MURRAY, JR. BY

'58 MARCUS L. BATES United States Patent 3,426,687 ZONE SELECTOR ACTUATED BY VENT LINE Clarence Murray, Jr., 708 Devonian, Midland, Tex. 79701 Filed Feb. 8, 1967, Ser. No. 614,659 US. Cl. 103-4 Int. Cl. F04b 23/00, 47/00; E21b 43/14 Claims ABSTRACT OF THE DISCLOSURE Background of the invention Oil wells often have several different zones or strata from which oil may be produced. The location of the various oil bearing formations, or strata, is ascertained after the well has been drilled, and the stratum which is selected for production depends upon various economic considerations. It is possible to perforate the casing adjacent two different oil bearing strata, allow the oil from each stratum to co-mingle, and simultaneously pump oil from both strata with a single oil pump. When this method of production is carried out, the producer sometimes suifers a severe penality, because the oil production allowable is then generally based upon the flow data of only one of the strata, and accordingly there is no economic gain realized by utilizing this expedient. Where it is possible to prevent the oil that is produced from one stratum from co-mingling or mixing with the oil within another stratum, the production allowable is then based upon the capabilities or flow data of each individual formation or stratum. The latter expedient is a decided economic gain over the first in many areas of the.country.

Various prior art devices are known for attaining simultaneous production from two different strata while at the same time maintaining the oil produced from each stratum separated until it is brought to the surface. These devices generally employ dual pump means having concentric pump actuating means; while still other devices employ electrically actuated solenoids for the purpose of changing the production from a first stratum to a second stratum, such as exemplified by the patent to Hebart, No. 2,852,079.

Summary It is therefore desirable in the production of dual completion wells that employ artificial fluid lift, wherein either a bottom-hole pump or other known device provides the lifting means for the oil, to provide both a method and apparatus for selectively producing each individual stratum independent of the remaining stratum while at the same time preventing the flow of oil from one stratum to another. It is further desirable to be able to test flow a well in a manner that enables determination of the production rate from any one of a multiplicity of zones. This expedient is attained in accordance with the present invention by connecting each stratum to the oil lifting means by a suitable valve means having dual inlets and a single outlet, wherein each inlet is connected to a diiferent stratum, and the valve is positioned by vertical movement of the vent string, wherein the vent string also vents the gas production from the lower stratum.

Accordingly, the primary object of this invention is to provide a method and apparatus for producing oil from 3,426,687 Patented Feb. 11, 1969 dual production zones in a well, wherein the oil produced by each zone cannot possibly flow from one zone into the other.

Another object of this invention is to provide a means by which a down-hole oil pump, or other oil lifting means, may be selectively communicated to either one of or both of the oil bearing strata in a dual completed oil well.

Still another object of this invention is to provide a valve means which is actuated in conjunction with the vent line in a manner that selectively communicates either of two different oil bearing strata of a dual completed oil well.

Still another object of this invention is to provide a valve means which is actuated in conjunction with the vent line in a manner that selectively communicates either of two different oil bearing stratum of a dual completed oil well with the oil lifting means.

A still further object of this invention is the provision of a method of producing a dual completed oil well in a manner that precludes co-mingling of the oil that is produced from one stratum with another stratum, and wherein the vent line associated with the oil well provides the means by which the stratum to be produced is controllably selected.

In carrying this invention into practice, and in order to exemplify the means by which the present method may be carried out, several new and useful apparatus have been brought into existence. Accordingly, the apparatus disclosed herein in order to teach the method of the present invention constitutes inteliectual subject matter that is also considered a part of this invention.

Brief description of the drawings FIGURE 1 is a partly diagrammatic assembly view showing the present invention in its relationship to an oil well, with some parts being shown in section, and other parts being shown in full view;

FIGURE 2 is an enlarged fragmentary view of a modification of part of the device seen in FIGURE 1;

FIGURE 3 is an enlarged fragmentary view of still another modification of the invention disclosed in FIG- URE 1;

FIGURE 4 is an enlarged cross-sectional view taken along line 44 of FIGURE 3;

FIGURE 5 is a fragmentary enlarged cross-sectional view of still another modification of FIGURE 1, that can be used in conjunction with the present invention; and

FIGURE 6 is a fragmentary view of a modification of FIGURE 3, with some parts cut away and shown in section in order to better illustrate the device.

Description of the preferred embodiments Referring to the drawings, FIGURE 1 shows an oil well 10 having a casing 12 associated therewith in the customary manner. The casing is provided with perforations 14 at an upper oil producing stratum and perforations 16 at a lower oil producing stratum. Above the ground level and attached to the upper depending end of the casing there is illustrated a supply tubing 18 having an outlet 20 through which oil flows to a tank battery or other gathering system. A conventional pump jack packing nut 22 reciprocatingly receives a conventional polish rod portion of a sucker rod 24 in sealed relationship therethrough. A conventional pumping jack apparatus (not shown) reciprocates the polish rod in a vertical direction, as is known to those skilled in the art. A vent line 26 that provides for the removal of gas production from the lower stratum is suitably disposed through a second packing nut 28 to enable the vent line to be vertically positioned with respect to the casing 12 in a manner similar to the operation of the polish rod. Spaced apart hydraulic lifting means 30 and 32, which may be similar to a conventional hydraulic jack, with each including a cylinder 34 and a piston 36 wherein hydraulic pressure applied at the base of the cylinder 34 and 34 lifts or lowers the piston 36 and 36' in a vertical direction. Cross-member 38 is suitably afiixed in a removable or adjustable manner to the vent line and to the free ends of the upstanding spaced apart pistons. A timer 39 actuates the pistons at predetermined intervals of time, usually based on the production history of the well. A nipple 40 having a valve 42 thereon communicates the inside of the casing with a flow line open to the atmosphere in the usual manner. The last mentioned valve may be used to vent the upper zone, as well as testing for communication between the different zones or strata of the well.

Suitably positioned between the upper and lower strata 14 and 16, there is seen a packer 44 which separates the upper and lower strata from each other, while at the same time permitting tubings 18 and 45 to communicate therethrough. Such a packer is known to those skilled in the art, and one example of many packers that may be used for the purpose illustrated at 44 is a Baker Retainer Production Packer (product number 733-03, manufactured by the Baker Oil Tools, Inc., 7400 East Slauson Ave., Los Angeles, Calif). The packer is provided with anchoring means 46 that rigidly holds the packer adjacent to the inside peripheral surface of the casing, while the expansible seal 48 prevents fluid flow between the outside periphery of the packer and the inside wall of the casing. The lower 'free end of the tubing 18 and the upper free end of the tubing 18 are received by the packer in the illustrated manner so as to provide communication therebetween. The packer also provides a means by which the upstanding tubing 45 and the upper free end of the tubing 45' may be sealingly fiow connected through the packer. Tubing 18 is sealed at the lower extremity by a bull plug 49, and a cross-over 50 communicates tubing 18 with tubing 45. Inside the tubing 18' there is seen a conventional downhole oil pump 51 which is actuated by the before mentioned reciprocating sucker rod 24. Other lifting devices may be used in lieu of the oil pump, while remaining within the scope of this invention.

The lower extremity of the tubing 45' is provided with the illustrated apertures seen at 52. Attached to the inside peripheral wall, near cross-over 50, is an upper valve seat 54 and a lower valve seat 56, with each valve seat being spaced apart adjacent cross-over 50, The vent line 26, sometimes also called the vent string, is open at 58 and carries a valve 57 thereon. The outside diameter of the elongated valve element 57 is of a selected size to fit in close tolerance relationship within the central passageway provided by the upper and lower spaced apart valve seats 54 and 56. External seal means, such as O-rings, may be provided on the outer peripheral wall of the valve element 57, if desired.

FIGURE 2 illustrates another embodiment that is similar to the device seen in FIGURE 1, and includes a supply tubing 18', crossover 50, and valve arrangement 53 with each of these elements being identical to the corresponding elements of FIGURE 1. The packer 60 is provided with anchoring means 61 and seal means 62. Upstanding tubing 63 communicates perforations 14 with the interior of tubing 45'. The packer includes a passageway 65 having inlet 66 which communicates the portion of the casing above perforations 16 with outlet 67. Passageway 68 of the packer receives a snap latch assembly 70 in close tolerance relationship therewithin. The snap latch assembly is provided with a central passageway 74 which reciprocatingly receives in sealing relationship therewith the before mentioned vent line 26. The outer periphery of the snap latch assembly is provided with upper seals 75 and lower seals 76 in the illustrated manner to prevent fluid flow along the inside peripheral wall surface of the passageway 68. Between the inside peripheral wall surface of the passageway 74 and the outside peripheral surface of the vent line 26', there is provided upper seal 77 and lower seal 78. The vent line 26 is provided with a series of longitudinally extending slots 80 that always provides a flow path between the interior of vent line 26 and inlet 66, for all normal positions of the valve assembly. The enlargements 27 and 27 are suitably spaced apart near the snap latch assembly to facilitate installation and removal of the device.

FIGURES 3 and 4 illustrate still another modification of the valve arrangement seen in FIGURES 1 and 2. As seen in FIGURE 3, a first valve and a second valve 86 are connected to the cross-over 88 by the conduits 90 and 91. Valve 85 is connected to tubing 92 by conduit 94. Conduit 95 communicates with upper perforations 14. The lower perforations 16 are connected to the cross-over by means of valve 86 and tubing 94.

Valves 85 and 86 are ball type valves that include a ball valve arrangement having a passageway therethrough whereby rotation of the valve stem 90 moves the ball valve therein from the fully open to the fully closed position. One valve of this type is manufactured by the Worcester Valve Co., Inc., 16 Parker Street, Worcester, Mass. When valve 85 is fully opened, valve 86 is fully closed, and vice versa. Valve 85 is actuated by rotational motion of valve stem 96. The valve stem is rigidly attached to a valve stem handle 98 which cooperates with a slot 100 of limited length that is provided within the rod 102. Rod 102 is removably attached to vent line 104 by coupling member 106. The lower ball valve 86 is likewise provided with a rotatable valve stem 108 to which there is rigidly attached a handle 110 that is actuated by the slot 112 provided in the rod 102.

FIGURE 5 illustrates still another modification of a valve assembly that may be used in conjunction with the apparatus illustrated in the above figures. The valve arrangement includes a vent line having a depending end 158 that may be either open or closed, depending upon the configuration of the device (FIGURES 1 or 2) with which the valve apparatus is to be used. A first valve seat is located in tubing 45'. A second valve seat 122 is spaced apart from the first valve seat with the cross-over 250 being located therebetween. A first element 124 is adapted to be seated in the illustrated manner upon proper positioning of the vent line 116. A second valve 126 that is adapted to seal against its corresponding seat is carried by the vent line 116. Abutment 128 is rigidly attached to the vent line 116 and a shoulder 130 is provided a spaced apart distance from the abutment. A spring 132 is maintained in compressed relationship between the valve and the abutment. The lower valve element is likewise provided with a shoulder 134, abutment 136, and a spring 138. Valve elements 124 and 126 are provided with O-rings so as to permit the illustrated reduced area of vent line 116 to sealingly reciprocate therein.

FIGURE 6 illustrates still another embodiment of the invention, wherein oil from a lower zone flows to the oil lifting means through conduit 194 and cross-over 188, while oil from above packer 60 flows down conduit 192, through valve 185, and to the oil lift means through cross-over 188. The valve is moved from the opened to the closed position by vertical movement of rod 202 which is actuated by the vent string. The rod 202 is attached to the vent string by means of coupling member 106. Valve stem 196 is rotated by radially extending handle 198 which is slidably received within the illustrated slot of the rod.

Operation In operation, oil may be produced from either of the strata adjacent perforations 14 or 16 by selectively positioning the valve assembly 53 of FIGURE 1. This is accomplished by actuating vent line 26 in a vertical direction by the hydraulic lifting means 30 and 32. With the valve 53 positioned in the illustrated position of FIGURE l, the oil entering the casing through perforations 16 flows through aperture 52 and into the lower extremity of tubing 45', however the oil cannot enter the cross-over 50 since valve 57 is sealingly engaged with valve seat 56. Accordingly, production is being carried out from the upper stratum associated with perforations 14, wherein the oil flows through the perforations 14 into the portion of the casing 12 above packer 44, where the oil then flows through the open end of upstanding tubing 45, through the packer, through tubing 45, through unseated valve seat 54, to the cross-over 50, where it is then lifted by the downhole pump 51 and accordingly moved through the production or supply tubing 18', through the packer 44, through the supply tubing 18, to where the oil exits at outflow line 20. Upon obtaining the allowable production for the month, or alternatively, upon the oil bearing stratum associated with perforations 14 being produced an optimum amount, the hydraulic lifting means 30 and 32 are supplied with hydraulic pressure below the lifting pistons 36 and 36', to thereby raise cross-member 38 a predetermined amount dependent upon the construction of valve 53, which in turn raises the vent line 26. Means for limiting the travel of the vent line 26 may be included downhole.

Upon lifting vent line 26 a predetermined amount, valve 57 will be unseated from valve seat 56 and seated within the valve seat 54, since the valve element 57 is slidably received within each of the seats. This action of unseating valve 57 from valve 56 seals off the flow of oil from the upper perforations 14 and permits oil to flow from the lower perforations 16 into the casing, through apertures 52, through valve seat 56, through cross-over 50, to where the oil may be lifted to the surface along the before described path by means of the downhole pump 51. Gas inlet 58 is preferably positioned near the bottommost part of valve seat 54 to thereby provide an outlet for any vapors contained in the oil. A bafiie placed at the upper portion of cross-over improves the effectiveness of the vapor trap. Accordingly, the device of FIG- URE 1 enables selective production from either one of the stratum associated with a dual completed well, by merely raising or lowering the vent line a predetermined amount in a vertical direction to thereby actuate a valve means in the above described manner. It will now be appreciated by those skilled in the art that the oil reservoir associated with the stratum at perforations 14 and 16 can never co-rningle for the reason that the valve 57 is always seated in either the valve seat 56 or valve seat 54, and is never simultaneously unseated from both valve seats unless it is deliberately raised beyond the stops that limit its normal range of travel. It will furthermore be appreciated that the valve 57, in conjunction with valve seats 54 and 56, permits production from either the upper or lower stratum, or alternatively, both stratum may be closed off by stopping the vertical travel of valve 57 while it is sealingly located within both valve seats.

In the operation of the device illustrated in FIGURE 2 of the drawings, it is to be understood that the upper portion of the casing 12' is identical to the illustration of FIGURE 1, and accordingly description of the operation thereof is considered unnecessary. As seen in FIGURE 2, the packer 60 is different in design than the before mentioned packer 44 since it includes upstanding tubing 63 that communicates the interior of tubing 45 with upper stratum adjacent perforations 14 by means of passageway 64. The vent line 26 is open at the lower free end thereof, as indicated by the numeral 58, although the free end may be closed at 58' if desired. The valve arrangement 53 is substantially identical to that of FIGURE 1. The vent line 26' vents the lower reservoir by means of passageway 65 which provides a flow path for gases from inlet 66, along passageway 65, through outlet 67, slots 80, into the vent line 26, and then to a point above the surface of the ground where the gases are vented in the usual manner from a point above the before mentioned hydraulic lifting cylinders by means of the terminal end portion of the vent line.

With valve assembly 53 in the illustrated position of FIGURE 2, oil from perforations 14 accumulates above the packer 60 and accordingly flows through the upstanding tubing 63, through passageway 64, into the tubing 45, through unseated valve seat 54, cross-over 50, and back into the outlet 20 along the before described path that includes tubing 18. It should be noted that the lower stratum is being vented while the valve 53 is in this position. When it is desired to shift production from the upper stratum to the lower stratum, the vent line 26' is raised in a vertical direction a predetermined amount whereby valve 57 enters the valve seat 54 to thereby seal cross-over 50- from stratum 14 and provide a flow between cross-over 50 and the lower perforations 16. With valve arrangement 53 in the opposite position to that illustrated in FIGURE 2, oil from perforations 16 flows through apertures 52, through the valve seat 56, cross-over 50, through the supply tubing 18', and along the before mentioned path to the outlet 20 above the ground.

Gas which may accumulate below the packer 60 is vented along the following flow path: inlet 66, passageway 65, outlet 67, slots 80, vent string 26, to where the gas is disposed of above the ground level by .means of the upper terminal end of the vent pipe in the usual manner. The lower extremity of the vent string is left open at 58' so as to act as a scavenger to thereby remove any gas which may be present at this location.

The snap latch assembly 70 may be removed from the packer together with the vent string 26 and 26'. This is accomplished by lifting the vent string 26, 26' vertically upward whereby valve 57 is removed from the lower valve assembly 53 and the enlargement 27' located on the vent string will thereby engage the shoulder on the lower extremity of the snap latch assembly 70 and accordingly unseat the device at release means 72 whereupon the entire vent string, snap latch assembly, and valve element 57 may be removed from the upper terminal end portion of the casing 12, should it be deemed desirable to do so. The enlargement 27 enables replacement of the snap latch assembly. The upper and lower enlargements 27 and 27 are spaced apart on the vent string an amount that exceeds the travel limit of the valve assembly 53. The portion of the vent string that moves within the snap latch assembly is preferably polished. The joints that connect the vent string are preferably located above and below the enlargements so as to present a smooth surface to the seals 77 and 78.

In the device illustrated by FIGURE 3, two independent ball valves and 86 are rigidly attached to the tubing 92 and provided with the illustrated flow conduits. The device of FIGURE 3 includes a suitable packer 60 that is substantially identical to the packer 60- of FIGURE 2. It should he understood that it is within the comprehension of this invention to locate valves 85 and 86 Within the tubing 92; however, in order to better illustrate the device, and for clarity, the valves are illustrated as being external of the tubing. In the modification of FIGURE 3, oil is produced from the upper stratum by positioning the valves in the illustrated manner, whereby oil entering tubing 92 flows through conduit 94, through opened valve 85, conduit 90, cross-over 88, and up along the flow path de scribed by the supply tubing 18' to outlet 20in the before described manner.

Where valves 85 and 86 have a small passageway through the rotatable ball element, it is possible to stop production from both strata, sometimes called shutting in the well. This is accomplished by lowering the vent line 104 a predetermined amount to enable each of the valves 85 and 86 to be rotated only 45, to thereby close off the flow path through both valves and accordingly stop flow from both the upper and lower stratum.

With valves 85 and 86 in the illustrated position of FIGURE 3, wherein the well is being produced from the upper stratum, and no flow can possibly occur from the lower stratum, the vent string 104 may be lowered a predetermined amount to rotate valves 85 and 86 their full limit of travel, which is accomplished by a rotational movement of 90, to thereby close valve 85 and open valve 86 whereby flow from the lower stratum may now enter the downwardly depending tubing 94, valve 86, con duit 91, cross-over 88, whereupon the oil is then lifted through the supply tubing 18' to the before mentioned outlet 20. Hence it may be seen that only one of the valves, 85 or 86, may be opened at the same time, and when one of the valves are moved from opened to closed position, both valves are closed during the transition from opened to closed position, and vice versa. Accordingly, communication between the different strata is never attained with the device of FIGURE 3.

FIGURE 4 is a side view of the device that further illustrates the method by which the valves 85 and 86 are actuated by the vent string 104. Since the Vent string 104 is coupled to a rod 102 by means of element 106, movement of the rod 102 vertically enables rotation of the valve 7 stem 98 by means of the slot 100 whereby the valve stem 96 is rotatably actuated in accordance to the vertical position of the slot 98 that is carried within the rod 102. In other words, vertical movement of rod 102 imparts rotational movement to valve stem 96 or 108. It is also considered within the comprehension of this invention to position the upper and lower valves by rotational movement of the vent string.

FIGURE 5 illustrates still another form of a valve that may be used in conjunction with the present invention, wherein the valve assembly 114 is suitably connected to a cross-over 250 that is identical to the cross-over as seen at 50 in FIGURES 1 and 2. It should be understood that flow from the upper stratum passes through valve seat 120, and that flow from the lower stratum passes through the valve seat 126. The device of FIGURE 5 is illustrated as being in the position that provides flow from the lower stratum since the valve 124 is being closed. When it is desired to shift production from the lower to the upper stratum, the vent line 116 is vertically raised a predetermined amount to thereby close valve 126, after which valve 124 is lifted by shoulder 130 from valve seat 120 to thereby permit flow from the upper stratum while preventing flow to occur from the lower stratum. The shoulders 130 and 134 are spaced apart on the vent line 116 whereby both valves are always closed during the transition period when changing flow from one stratum to another. It is advantageous to employ springs 132 and 138 that may be fully compressed between the abutment and the valve so as to prevent damage when one of the abutments fully compresses a spring associated therewith.

The embodiment of FIGURE 6 is used in conjunction with a well having two different oil producing strata that are normally comingled within conduit 188 prior to the oil being pumped to the surface of the ground. Valve 185 may be moved to the closed position, thereby stopping production from the upper stratum, while permitting the production from the lower stratum to be carried out by means of open ended conduit 194. This expedient enables the production characteristics of each stratum to be calculated, and the monthly production rate of both zones or strata to be adjusted according to the results of the calculations.

It should be understood that when using the valve of FIGURE 5 in conjunction with the embodiment of FIG- URE 1, the vent string 116 should remain open at the lower end thereof; however, the vent string 116 may either be closed or opened at the lower terminal end when used in conjunction with the device illustrated in FIGURE 2.

It should be understood that the casing in each of the above examples may be several thousand feet in length, and that the distance between adjacent producing zones or oil bearing strata may be on the order of several hundred feet. Furthermore, the relative position of the perforations 14 or 16 with respect to the packer is not to be understood as having the precise relationship as set forth in the drawings. For example, the distance from packer 60 to the valve assembly 53 could be 1200 feet, and the distance between the enlargement 27 and the valve element 57 could be of the same order.

While I have described this invention in its broader aspects, it is not limited to the specific methods and mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. In a multi-completed oil well, having an oil lifting means associated therewith, a packer means between adjacent oil producing strata, and a vent string for venting compressible fluids from the well, the method of selectively flowing oil from either adjacent stratum comprising the steps:

(1) flow connecting each adjacent stratum to a common point;

(2) flow connecting the common point to the oil lifting means;

(3) selectively interrupting the flow between the common point and one of the adjacent strata;

(4) using the vent string to provide mechanical movement in carrying out step (3) to selectively interrupt the flow.

2. The method of claim 1 wherein the oil well is a dual completed well; the common point is located below the packer; and including the following additional steps:

(5) providing a threeway valve means at the common point for providing the function of step (3), wherein the valve means includes dual inlets with each inlet connected to a different stratum, and with the outlet connected to the lifting means;-

(6) carrying out step (4) by actuating the three-way valve means with the vent string.

3. In combination with a well having a multiplicity of oil producing strata, with two strata being flow connected to the casing of the oil well and separated from each other by a packer or the like, a supply tubing sealingly extending through the packer and including oil lifting means, a vent line extending into the casing for venting the casing below the packer; the improvement comprising:

means for means; one of said means for flow connectlng including a valve means for selectively interrupting the flow from one stratum to the lifting means,

means connecting the vent line to said valve means to thereby enable mechanical movement of the vent line to selectively actuate said valve means whereupon oil can flow from either stratum to the lifting means.

4. The improvement of claim 3, and further including means whereby said vent line sealingly and slidably extends through said packer, and said valve means includes a three way valve having two inlets and one outlet, with means for selectively permitting flow from one inlet to said outlet while stopping flow from the remaining inlet to the outlet;

said outlet including conduit means connected to said lifting means;

said vent line including means for selectively moving said three way valve to thereby permit flow from either of the strata.

5. The improvement of claim 4 wherein said three way valve includes spaced apart valve seats with said conduit means flow connected therebetween;

said vent line includes a longitudinally extending valve member received thereabout;

said valve member being slidably received in close tolerance relationship within said valve seats;

whereby longitudinal movement of said vent string flow connecting each stratum to the lifting withdraws said valve member from one valve seat to thereby permit flow therethrough while remaining within the other valve seat to prevent flow therethrough.

6. The improvement of claim 4 wherein said three way valve includes spaced apart valve seats with said conduit means flow connected therebetween;

said vent line having spaced apart shoulders, spaced apart abutments, spaced apart compression means, and spaced apart valve members;

each said valve member adapted to be seated on said valve seat;

each said valve member being centrally and slidably received by said vent string and including seal means therebetween; each said valve member being urged against said shoulder by said compression means with said compression means being held in compressed relationship between said valve member and said abutment;

each shoulder being spaced apart relative to said seat whereby both valve members are resiliently seated on said valve seat in one position, and either valve member can be unseated after the remaining valve member is seated.

7. The improvement of claim 4 wherein said valve means includes two ball type valves;-

one valve being connected between said conduit means and one stratum;

the remaining valve means being connected between said conduct means and the remaining stratum;

said vent line including means associated with said valves whereby flow from either stratum to the lifting means may be selected by manipulation of the vent line.

8. The improvement of claim 3, wherein said valve means includes a first inlet connected to the stratum above the packer means, a second inlet connected to the stratum below the packer means, and an outlet connected to the lifting means;

said valve means having a valve member associated therewith whereby in a first position flow occurs from the upper stratum to the lifting means while flow is effectively stopped from the lower stratum to the lifting means; and in a second position flo'w occurs from the lower stratum to the lifting means 5 while flow is effectively stopped from the upper stratum to the lifting means; and in positions intermediate the said first and second positions, flow is efiectively stopped between both the upper and lower stratum and the lifting means, whereby:

flow from either stratum into the remaining stratum is effectively eliminated.

9. The improvement of claim 8, wherein the vent line extends in sealed and slidable relationship through said packer means;

means forming a passageway in the packer means that communicates the lower stratum with the interior of the vent line;

and means for removing a portion of the means for connecting, along with the vent string and the portion of the packer means through Which the vent string passes.

10. The improvement of claim 3 wherein the vent string extends in sealed and slidable relationship through said packer means;

means forming a passageway in the packer means that communicates the lower stratum with the interior of the vent string;

and means for removing a portion of the means for connecting, along with the vent string, and the portion of the packer means through which the vent string passes.

References Cited UNITED STATES PATENTS 2/1954 Hoflfer 1034 9/1958 Hebard 166-147 

